Position indicator

ABSTRACT

A position indicator that can be used with a plurality of types of position detection systems. The position indicator includes a first transmitter, a second transmitter, an input circuit which, in operation, accepts an input from outside of the position indicator, a signal generation circuit which, in operation, generates a position detecting signal, a plurality of additional information generation circuits which, in operation, generate a plurality of types of additional information, and a controller. The controller controls, based on the input accepted by the input circuit, transmission of the position detecting signal through the first transmitter and controls, based on the input accepted by the input circuit, transmission of additional information generated by the plurality of additional information generation circuits from the first transmitter or the second transmitter.

BACKGROUND

Technical Field

The present disclosure relates to a position indicator (stylus) for usewith a position detection sensor.

Description of Related Art

As a position inputting apparatus configured from a position detectionsensor and a position indicator called electronic pen, various positioninputting apparatuses of various schemes such as, for example, anelectromagnetic coupling scheme and a capacitive coupling scheme areavailable depending upon a difference in coupling scheme between theposition detection sensor and the electronic pen.

Further, even for position inputting apparatuses of a same scheme,various configuration types are available depending upon a difference inan exchanging method of a position detecting signal between the positiondetection system and the position indicator and a method for exchangingadditional information such as manipulation information of a switchprovided on the position indicator, writing pressure information,identification information of the position indicator, and internalstorage data or for exchanging instruction information for changing anaction of the position indicator. Conventionally, a position indicatorcompatible with a position detection system is provided to userslimitatively by a method of a specific position detecting signal and amethod of exchanging additional information. Therefore, since it isnecessary for a user to have position indicators for exclusive use forposition inputting apparatus which include position detection systemshaving similar position detection sensor means, it is necessary for theuser to carry a plurality of position indicators and select anappropriate position indicator for each of position inputting apparatus.

For example, as a position indicator of the capacitive coupling scheme,such a plurality of configuration types as described below areavailable. In particular, a position indicator of a first configurationtype is a position indicator of a scheme (passive scheme) wherein theposition indicator does not send out a position detecting signal but AC(Alternating Current) electric field energy sent out from a sensorcircuit of the position detection system flows to the earth (ground)through the position indicator and a human body to detect a variation ofenergy (or a voltage) induced in a conductor of the sensor circuit ofthe position detection system at a position at which the positionindicator exists to detect the position (refer, for example, to PatentDocument 1 (Japanese Patent Laid-Open No. 2011-3035)).

Meanwhile, a position indicator of a second configuration type of thecapacitive coupling scheme is a position indicator of a scheme (improvedtype of the passive scheme) which is an improvement of the firstconfiguration type described above, which is low in sensitivity inposition detection, and which receives a signal from the sensor circuitof the position detection system, performs signal processing such assignal enhancement of the received signal and feeds back the processedsignal to the sensor circuit (refer, for example, to Patent Document 2(Japanese Patent No. 4683505)). In the case of the position indicatorsof the first and second configuration types, additional information istransmitted or exchanged to the position detection sensor using, forexample, wireless communication means.

A position indicator of a third configuration type of the capacitivecoupling scheme is a position indicator of an active scheme in which,different from those of the first and second configuration typesdescribed above, the position indicator includes a sending circuit andan outgoing signal from the sending circuit is supplied as a positiondetecting signal to the position detection sensor (refer, for example,to Patent Document 3 (Japanese Patent Laid-Open No. 1995-295722)). Theposition detection system uses a sensor panel of position detectionmeans and performs position detection of a position indicated by theposition indicator from signal strengths of individual conductors bywhich the outgoing signal from the position indicator of the activescheme is received.

Further, position indicators of the third configuration type are furtherdivided into a plurality of types including a configuration type inwhich additional information is sent to and received from the positiondetection system together with a position detecting signal and anotherconfiguration type in which part of the additional information is sentand received together with a position detecting signal and the remainingadditional information is transmitted separately to a wirelesscommunication means provided in the position detection system through awireless communication means.

It is to be noted that, although a detailed description is omitted, alsoin the position indicator of the electromagnetic coupling scheme, aplurality of configuration types are available including a configurationtype in which a signal from the sensor circuit of the position detectionsystem is received by a resonance circuit and the received signal is fedback to the sensor circuit of the position detection system, anotherconfiguration type in which a sending circuit is provided and anoutgoing signal from the sending circuit is transmitted to the sensorcircuit of the position detection system through a resonance circuit,and a further configuration type in which additional information istransmitted to a wireless communication means provided in the positiondetection system, similarly as in the case of the capacitive couplingscheme described hereinabove.

Prior Art Documents Patent Documents

-   Patent Document 1: Japanese Patent Laid-Open No. 2011-3035-   Patent Document 2: Japanese Patent No. 4683505-   Patent Document 3: Japanese Patent Laid-Open No. H07-295722

BRIEF SUMMARY Technical Problems

Incidentally, even for position inputting apparatuses of the samecapacitive coupling scheme or electromagnetic induction scheme, if theconfiguration type is different, a position indicator corresponding tothe configuration type must conventionally be prepared as describedhereinabove. However, that a position indicator must be prepared forevery different configuration type in such a manner described aboveimposes a burden on the user in terms of the cost, and the user mustmanage position indicators of a plurality of configuration types in acoordinated relationship with position detection systems, which iscumbersome.

It is an object of the present disclosure to solve the foregoingproblems and provide a position indicator by which a plurality ofconfiguration types can be utilized.

Technical Solution

In order to solve the problems described above, according to the presentdisclosure, there is provided a position indicator, including: a firsttransmitter; a second transmitter; an circuit input circuit which, inoperation, accepts an input from outside of the position indicator; asignal generation circuit which, in operation, generates a positiondetecting signal; a plurality of additional information circuits which,in operation, generate a plurality of types of additional information;and a controller which, in operation, controls, based on the inputaccepted by the input circuit, transmission of the position detectingsignal through the first transmitter and controls, based on the inputaccepted by the input circuit, transmission of additional informationfrom the plurality of additional information generation circuits fromthe first transmitter or the second transmitter.

In the position indicator according to the present disclosure having theconfiguration described above, on the basis of an input accepted by theinput circuit, the controller (e.g., microprocessor) controlstransmission of a position detecting signal through the firsttransmitter and controls transmission of additional information from theplurality of additional information generation circuit from the firsttransmitter or second transmitter.

Consequently, the position indicator according to the present disclosurecan configure itself as a plurality of types of position indicatorscompatible with position detection systems of various configurationtypes (modes).

Advantageous Effect

Since the position indicator according to the present disclosure canadopt, in response to a configuration type of a position detectionsystem, a configuration (mode) suitable for the configuration type, thenecessity for preparing a position indicator for each of positiondetection systems of different configuration types is eliminated, andthe burden on the user in terms of cost can be reduced. Further, sinceonly it is necessary for the user to obtain a single position indicatorcommon to a plurality of position detection systems of differentconfiguration types, an advantageous effect that the necessity forcomplicated management corresponding to position detection systems iseliminated can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view depicting a configuration of a position indicatoraccording to an embodiment of the present disclosure.

FIGS. 2A and 2B are views depicting an example of a mechanicalconfiguration of a position indicator according to an embodiment of thepresent disclosure.

FIG. 3 is a sectional view depicting an example of a detailedconfiguration of part of a mechanical configuration of a positionindicator according to an embodiment of the present disclosure.

FIG. 4 is a block diagram depicting a conceptual configuration of aposition indicator according to an embodiment of the present disclosureand processing action of the same.

FIG. 5 is a view depicting part of an example of a conceptualconfiguration of a position indicator according to an embodiment of thepresent disclosure.

FIG. 6 is a view depicting part of a flow chart illustrating an exampleof a flow of processing operations of a position indicator according toan embodiment of the present disclosure.

FIG. 7 is a view depicting part of a flow chart illustrating an exampleof a flow of processing operations of a position indicator according toan embodiment of the present disclosure.

FIG. 8 is a view depicting an example of a position indicator of aconfiguration type which can be configured according to an embodiment ofthe present disclosure.

FIG. 9 is a view depicting an example of a position indicator of aconfiguration type which can be configured according to an embodiment ofthe present disclosure and a compatible position detection system.

FIG. 10 is a view depicting another example of a position indicator of aconfiguration type which can be configured according to an embodiment ofthe present disclosure and a compatible position detection system.

FIG. 11 is a timing chart illustrating the example of FIG. 10.

FIG. 12 is a view depicting still another example of a positionindicator of a configuration type which can be configured according toan embodiment of the present disclosure and a compatible positiondetection system.

FIG. 13 is a timing chart illustrating the example of FIG. 12.

FIG. 14 is a view depicting a further example of the position indicatorof a configuration type which can be configured from the embodiment ofthe position indicator according to an embodiment of the presentdisclosure and a compatible position detection system.

FIG. 15 is a timing chart illustrating the example of FIG. 14.

FIG. 16 is a view depicting a flow chart illustrating an example of aflow of processing operations of a position detection system compatiblewith a still further example of a position indicator of a configurationtype which can be configured according to an embodiment of the presentdisclosure.

FIGS. 17A and 17B are views illustrating a yet further example of aposition indicator of a configuration type which can be configuredaccording to an embodiment of the present disclosure.

FIG. 18 is a view depicting a conceptual configuration of a positionindicator according to an embodiment of the present disclosure.

FIGS. 19A, 19B, and 19C are views depicting an example of a positionindicator of a configuration type which can be configured according toan embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS DISCLOSURE

In the following, embodiments of the position indicator according to thepresent disclosure are described with reference to the drawings. FIG. 1is a view generally depicting a conceptual configuration of a positionindicator 1 of an embodiment of the present disclosure and processingactions of the same and is a view illustrating a state in which theposition indicator 1 is positioned on a sensor inputting face 2 a of aposition detection system 2 of the capacitive type. Meanwhile, FIGS. 2Aand 2B are views depicting an example of a mechanical configuration ofthe position indicator 1. More particularly, FIG. 2AA is a partiallongitudinal sectional view of the position indicator 1 and FIG. 2BB isa view depicting part of an appearance of the position indicator 1. Inthe present embodiment, the position indicator 1 is formed such that anappearance thereof has a bar-like stylus shape.

Description of Example of Mechanical Configuration of Position Indicatorof Embodiment

The position indicator 1 of the present embodiment includes a bar-likehousing 3. This housing 3 is configured from an insulator portion 31 ofa hollow cylindrical shape made of an insulating material or a syntheticresin as depicted in FIG. 2A. Further, in the present embodiment, atleast a portion of an outer circumferential face of the insulatorportion 31 of the housing 3 at which an operator is to grasp theposition indicator 1 is covered with a conductor portion 32 made of, forexample, a metal.

In the housing 3, a printed wiring board 40, a battery 5 and a writingpressure detection circuit 9 are disposed as depicted in FIG. 2A. Theconductor portion 32 which covers an outer circumferential face of thehousing 3 is electrically connected, though not depicted, to a groundingconductor of the printed wiring board 40.

On the printed wiring board 40, a signal transmission control circuit 41configuring an example of a controller, a wireless communication circuit42, a side switch 43 formed from a pushbutton switch, an ID(Identification) memory 44 in which identification information (ID) ofthe position indicator 1 is stored, oscillators 45 and 46 which outputoscillation signals of frequencies f1 and f2 different from each other,and wire patterns such as conductor patterns 47 a to 47 e as well as, inthe present example, a power supply switch 48 and an LED (Light EmittingDiode) 49 and so forth are disposed as depicted in FIGS. 1 and 2A. It isto be noted that, while, in FIG. 2A, each of the conductor patterns 47 ato 47 e is schematically depicted as a single conductor pattern forsimplified illustration, each of the conductor patterns 47 a to 47 e maynaturally be formed from a plurality of conductor patterns as occasiondemands.

The battery 5 is a supplying source of power to electronic circuits andelectronic parts configured on the printed wiring board 40. The writingpressure detection circuit 9 is configured, in the present embodiment,as a variable capacitor which indicates a capacitance according to awriting pressure applied to a center electrode 7 which configures thecore member as hereinafter described.

The wireless communication circuit 42 has a transmission circuit whichmakes an example of a transmitter (second transmitter) of additionalinformation of the present disclosure and a reception circuit whichmakes an example of a receiver (first receiver) for receiving a signalfrom the position detection system and is configured, in the presentembodiment, as a wireless communication circuit that performs wirelesscommunications according to a defined communication protocol associatedwith the Bluetooth (registered trademark) standard, which is ashort-distance wireless communication standard. The wirelesscommunication circuit 42 is connected to the signal transmission controlcircuit 41. It is to be noted that the wireless communication circuit 42is not limited to a Bluetooth circuit but may be a circuit by, forexample, infrared communication, or a wireless communication circuit ofthe Wi-Fi (registered trademark) standard may be used.

The side switch 43, ID memory 44 and writing pressure detection circuit9 individually configure an additional information generation circuit.The side switch 43 supplies on or off information thereof as an exampleof additional information to the signal transmission control circuit 41.The ID memory 44 outputs identification information (ID) of the positionindicator 1 stored therein to the signal transmission control circuit 41as an example of additional information in response to a reading outrequest from the signal transmission control circuit 41. The variablecapacitor configured from the writing pressure detection circuit 9exhibits a capacitance variation in response to a writing pressure valueapplied to the center electrode 7 configuring the core member, and thesignal transmission control circuit 41 generates writing pressureinformation as an example of additional information on the basis of thecapacitance of the variable capacitor.

The oscillators 45 and 46 generate an AC signal for forming a positiondetecting signal to be transmitted from the position indicator 1 of thepresent embodiment and supplies the generated AC signal to the signaltransmission control circuit 41. In the present embodiment, theoscillator 45 generates an AC signal of the frequency f1, and theoscillator 46 generates an AC signal of the frequency f2, which isdifferent from the frequency f1. The signal transmission control circuit41 generates different position detecting signals on the basis of theoscillator 45 and the oscillator 46. In short, the signal transmissioncontrol circuit 41 cooperates with the oscillator 45 and the oscillator46 to configure a position detection signal generation circuit andconfigure two signal sending circuits. Then, the signal transmissioncontrol circuit 41 determines one of the two different positiondetecting signals generated thereby as a position detecting signal to betransmission from the position indicator 1. It is to be noted that, inplace of the oscillators 45 and 46, a plurality of signal sendingcircuits which generate and send position detecting signals for aplurality of position indicators of different configuration types of theactive scheme hereinafter described may be provided such that they areselectively controlled by the signal transmission control circuit 41.

Further, in the present embodiment, the battery 5 is configured so as tobe accommodated in the housing 3 in such a manner as depicted in FIGS. 1and 2A, and a power supply voltage for electronic circuit circuits suchas the signal transmission control circuit 41 on the printed wiringboard 40 is generated by the battery 5. In FIG. 2A, a terminal 52 is aterminal electrically connected to a power supply circuit on the printedwiring board 40. A positive side electrode 51 of the battery 5 contactswith and is electrically connected to the terminal 52. Though notdepicted, a negative side electrode of the battery 5 is directlyconnected to a grounding conductor of the printed wiring board 40 or ispressed against and contacts with an elastically displaceable terminalwhich is connected to the grounding conductor of the printed wiringboard 40 through the conductor portion 32 of the housing 3.

An operation element 48 a of the power supply switch 48 disposed on theprinted wiring board 40 is provided for manual operation from theoutside through an opening provided in the housing 3 as depicted in FIG.2B. The user can switch the power supply switch 48 on or off by slidablymoving the operation element 48 a. It is to be noted that, although apower supply circuit for generating a power supply voltage from thevoltage from the battery 5 when the power supply switch 48 is switchedon is formed on the printed wiring board 40, it is omitted forsimplified description in FIGS. 1 and 2A.

One end portion side in a center line (e.g., central axis) direction ofthe insulator portion 31 of the hollow cylindrical shape whichconfigures the housing 3 is formed as a tapered portion 33 which tapersgradually as depicted in FIG. 2A. A peripheral electrode 6 formed, forexample, from an annular conductor metal is attached to the outercircumference side of the tapering portion 33. The peripheral electrode6 and the conductor portion 32 on the outer circumferential face of thehousing 3 are isolated from each other because the insulator portion 31is interposed between them.

The peripheral electrode 6 capacitively couples to the positiondetection system 2 as schematically depicted in FIG. 1 to configure, inthe present embodiment, a reception circuit (second receiver) of asignal from the position detection system. Further, the peripheralelectrode 6 is electrically connected to the conductor pattern 47 a ofthe printed wiring board 40 by a lead conductor member 61 which extendsthrough the insulator portion 31. The conductor pattern 47 a isconnected, in the present example, to an input end of the signaltransmission control circuit 41.

Further, in the present embodiment, the center electrode 7 configuredfrom a bar-like member having conductivity is disposed such that one endside thereof projects to the outside from the hollow portion of thetapering portion 33 of the housing 3. This center electrode 7 serves asthe core member which configures a pen tip of the pen-shaped positionindicator 1.

The center electrode 7 configures, in the present embodiment, a firsttransmitter that transmits a position detecting signal, and isconfigured such that an end portion thereof on the side opposite to theside on which the center electrode 7 projects to the outside iselectrically connected to the conductor pattern 47 b formed on theprinted wiring board 40. The conductor pattern 47 b is connected to anoutput terminal of the signal transmission control circuit 41. It is tobe noted that, in the present embodiment, the position indicator 1 actsalso as a position indicator of the passive scheme which does not sendout a position detecting signal, and in this case, the center electrode7 plays a role in receiving electric charge from the conductor of theposition detection system 2 through an capacitive coupling portion.

The peripheral electrode 6 is provided around the center electrode 7.The combination of the peripheral electrode 6 and the center electrode 7is for a position indicator of the improved type of the passive schemedescribed hereinabove. In the present embodiment, between the peripheralelectrode 6 and the center electrode 7, a shield member 8 foreffectively preventing electric interference between them is provided.The shield member 8 in the present embodiment is provided in such amanner as to surround the center electrode 7, and consequently, theshield member 8 is interposed between the peripheral electrode 6 and thecenter electrode 7 to make the coupling capacitance between theperipheral electrode 6 and the center electrode 7 as low as possible.

The center electrode 7 as the core member is fitted at an end portionthereof on the side opposite to the side on which the center electrode 7projects to the outside with the writing pressure detection circuit 9disposed in the hollow portion of the housing 3 to lock the centerelectrode 7 in the hollow portion of the housing 3 of the positionindicator 1. It is to be noted that, as hereinafter described, thecenter electrode 7 is configured such that the fitting thereof with thewriting pressure detection circuit 9 is canceled by pulling out thecenter electrode 7. In other words, the center electrode 7 as the coremember is exchangeable with respect to the position indicator 1.

The writing pressure detection circuit 9 is configured, in the presentexample, from a variable capacitor (refer, for example, to JapanesePatent Laid-Open No. 2011-186803) which exhibits a capacitance accordingto a pressure (writing pressure) applied to the center electrode 7 asthe core member. Electrodes at the opposite ends of the variablecapacitor configured from the writing pressure detection circuit 9 areconnected to the signal transmission control circuit 41, in FIG. 2A,through the conductor pattern 47 c.

The signal transmission control circuit 41 performs determinationcontrol, on the basis of information received from the outside throughthe wireless communication circuit 42 or information received throughthe peripheral electrode 6, to which one of a plurality of configurationtypes (modes) the position indicator 1 of the present embodiment is tobe set. Further, the signal transmission control circuit 41 controls, onthe basis of the determination control, transmission of a positiondetecting signal through the center electrode 7 and further controlstransmission of additional information through the center electrode 7 orthe wireless communication circuit 42.

Now, a detailed configuration of a portion including the centerelectrode 7, shield member 8 and writing pressure detection circuit 9 isdescribed with reference to FIG. 3. FIG. 3 depicts a cross sectionalview of a portion including the center electrode 7, shield member 8 andwriting pressure detection circuit 9.

The center electrode 7 includes, as depicted in FIG. 3, a core member 71made of a conducive material, for example, a metal and formed with adiameter of, for example, 1.9 mm, and is, in the present embodiment,covered with a protective member 72 that extends on approximately halfof the pen tip side of the core member 71 and is made of an insulatingmaterial. The protective member 72 plays a role of preventing the sensorinputting face 2 a of the position detection system 2 from being damagedand increasing the contact area with the sensor inputting face 2 a andanother role of further strengthening the isolation of the shield member8 and the peripheral electrode 6 from each other.

As depicted in FIG. 3, the shield member 8 is configured in the presentembodiment such that a tubular member 81 configured from a conductivematerial is covered over an overall surface including an outer wall faceand an inner wall face thereof with an insulating layer 82.

The writing pressure detection circuit 9 is configured as a variablecapacitor whose capacitance varies in response to a writing pressureapplied to the center electrode 7 and acting upon the center electrode 7through a pressure transmission member 10. As depicted in FIG. 3, thecenter electrode 7 and the pressure transmission member 10 are coupledto each other and accommodated in a slidably movable state in the hollowportion of the tubular member 81 of the shield member 8. The pressuretransmission member 10 has a core member fitting portion 11 into whichan end portion 71 a of the core member 71 of the center electrode 7 isto be fitted, and a projection 12 which fits with the writing pressuredetection circuit 9.

Further, in a recessed portion 11 a of the pressure transmission member10, a terminal piece 13 for establishing electric connection between thecenter electrode 7 and the signal transmission control circuit 41 of theprinted wiring board 40 is disposed as depicted in FIG. 3, and anextension 13 a from the terminal piece 13 is connected to a leadelectrode 14 connected to the conductor pattern of the printed wiringboard 40.

The core member 71 of the center electrode 7 is inserted (force fitted)at an end portion 71 a thereof with the terminal piece 13 in therecessed portion 11 a of the core member fitting portion 11 of thepressure transmission member 10 so as to be coupled to the pressuretransmission member 10, and a writing pressure applied to the coremember 71 is transmitted to the writing pressure detection circuit 9hereinafter described through the pressure transmission member 10.

It is to be noted that, as depicted in FIG. 3, a conductive metal plate86 electrically connected to the grounding conductor of the printedwiring board 40 is provided at an abutting portion between the writingpressure detection circuit 9 and the shield member 8, and a terminalportion 83 at which the face of the tubular member 81 of the shieldmember 8 is exposed is electrically connected to the conductive metalplate 86. Consequently, the center electrode 7 is shielded against anelectric field by the shield member 8.

It is to be noted that, since the core member fitting portion 11 of thepressure transmission member 10 is engaged with a stepped portion 84 ofthe hollow portion of the tubular member 81 of the shield member 8, thecenter electrode 7 and the pressure transmission member 10 are preventedfrom falling out to the pen tip side. Further, a stepped portion 85 onthe outer circumferential face of the shield member 8 is engaged with astepped portion formed on the inner wall of the hollow portion of theinsulator portion 31 of the housing 3 not depicted such that the shieldmember 8 does not move in an axial direction in the hollow portion ofthe insulator portion 31 of the housing 3.

The writing pressure detection circuit 9 is described below. The writingpressure detection circuit 9 of the present example uses writingpressure detection means of a known configuration disclosed, forexample, in Patent Document: Japanese Patent Laid-Open No. 2011-186803and configures a variable capacitor whose capacitance varies in responseto a writing pressure applied to the center electrode 7.

The writing pressure detection circuit 9 of the present example isconfigured such that, as depicted in FIG. 3, a plurality of partsincluding a dielectric member 92, a conductive member 93, an elasticmember 94, a holding member 95 and a terminal member 96 are accommodatedin a housing member 91 configured from an insulating material, forexample, a resin. The terminal member 96 configures a first electrode ofa variable capacitor which configures the writing pressure detectioncircuit 9. Further, the conductive member 93 and the elastic member 94are electrically connected to each other to form a second electrode ofthe variable capacitor.

In the writing pressure detection circuit 9, if a writing pressure isapplied to the center electrode 7, then the writing pressure istransmitted to the holding member 95 of the writing pressure detectioncircuit 9 through the pressure transmission member 10, and the holdingmember 95 moves the conductive member 93 toward the dielectric member 92side in response to the applied writing pressure. Consequently, thecontact area between the conductive member 93 and the dielectric member92 varies in response to the applied writing pressure, and thecapacitance of the variable capacitor formed between the first electrodeand the second electrode varies in response to the applied writingpressure.

Description of Example of Configuration of Internal Electronic Circuitof Position Indicator 1 of Embodiment

In the present embodiment, as the position detection system 2 usedtogether with the position indicator 1, systems of a plurality ofconfiguration types of the passive scheme, improved type of the passivescheme and active scheme are available as described hereinabove. In thepresent embodiment, where the position detection system 2 includes awireless communication circuit that communicates with the wirelesscommunication circuit 42 of the position indicator 1, pen typeinformation indicative of a configuration type which allows action ofthe position detection system is transmitted to the position indicator 1by the wireless communication circuit. The position indicator 1 receivespen type information from the position detection system by the receptioncircuit (first receiver) of the wireless communication circuit 42,determines, on the basis of the received pen type information, to whichconfiguration type (mode) the position indicator is to be set itself,and controls the position indicator 1 itself so as to have aconfiguration as a position indicator of the determined configurationtype.

In the case of a position indicator whose configuration type is thepassive scheme or the improved type of the passive scheme in which atransmission signal from the position detection system 2 side isreceived, the position indicator 1 receives a signal from the positiondetection system through the peripheral electrode 6 (second receiver) todetermine to which configuration type it is to be set itself and cancontrol the position indicator 1 itself so as to have a configuration ofa position indicator of the determined type.

In this case, since the passive scheme and the improved type of thepassive scheme have a difference in frequency of a signal from aposition detection system or a difference in signal contents (differencein spread code, difference in modulation method and so forth), theposition indicator 1 decides the differences and determines to whichconfiguration type the position indicator 1 is to be set itself based ona result of the decision. In this case, even when information of aconfiguration type is not obtained from the position detection systemthrough the wireless communication circuit, it can be decided to whichconfiguration type (mode) the position indicator is to be set itself.

The signal transmission control circuit 41 of the position indicator 1performs a determination process of a configuration type (mode) of theposition indicator 1 based on the information received from the positiondetection system 2 through the wireless communication circuit 42 or on asignal received through the peripheral electrode 6 described hereinaboveand performs also a process for controlling the position indicator 1 soas to have the determined configuration type (mode).

FIG. 4 is a block diagram depicting a configuration of an electroniccircuit formed on the printed wiring board 40 in the housing 3 of theposition indicator 1 of the present embodiment and is a view depictingan example of a detailed internal configuration principally of thesignal transmission control circuit 41.

As depicted in FIG. 4, the signal transmission control circuit 41 isconfigured including a control circuit (i.e., controller) 410configured, for example, from an IC (Integrated Circuit), a pen typedecision circuit 411, a center electrode transmission signal generationcircuit 412, a wireless transmission signal generation circuit 413, aswitch circuit 414 for selection of a position detecting signal, afeedback signal generation circuit 415, and switch circuits 416 and 417for switching between a position indicator of the passive scheme and aposition indicator of the improved type of the passive scheme and theactive scheme.

To the control circuit 410, the variable capacitor configured from thewriting pressure detection circuit 9 is connected, and the controlcircuit 410 calculates a pressure (writing pressure value) applied tothe center electrode 7 from a capacitance of the variable capacitorconfigured from the writing pressure detection circuit 9. Further, an onor off state signal of the side switch 43 is supplied to the controlcircuit 410. The control circuit 410 generates, from the on or off statesignal of the side switch 43, side switch information which isadditional information relating to the side switch 43. Further, the IDmemory 44 is connected to the control circuit 410, and the controlcircuit 410 reads out and acquires the identification information (ID)of the position indicator 1 from the ID memory 44 as occasion demands.It is to be noted that the ID memory 44 may be accommodated in theposition indicator 1 with the identification information stored thereinin advance or may be configured such that the identification informationwhich is the storage contents of the storage ID memory 44 can berewritten by a command from the position detection system 2 which isreceived, for example, through the wireless communication circuit 42.

The control circuit 410 controls, in response to information based on apen type decision result from the pen type decision circuit 411, whetheror not each of a plurality of types of additional information, in thepresent example, each of writing pressure information, side switchinformation and identification information, is to be transmitted fromthe center electrode 7 or is to be transmitted by wireless transmissionfrom the wireless communication circuit 42.

The control circuit 410 supplies additional information to betransmitted through the center electrode 7 to the center electrodetransmission signal generation circuit 412 and supplies additionalinformation to be transmitted through the wireless communication circuit42 to the wireless transmission signal generation circuit 413.

The center electrode transmission signal generation circuit 412 isconnected to the center electrode 7 such that additional information tobe transmitted is transmitted to the position detection system 2 throughthe center electrode 7 together with a position detecting signal ashereinafter described. The wireless transmission signal generationcircuit 413 is connected to a transmission circuit (i.e. transmitter)421 of the wireless communication circuit 42 such that additionalinformation to be transmitted is transmitted by wireless transmission tothe position detection system 2 through the transmission circuit 421.

To the center electrode transmission signal generation circuit 412, anAC signal of the frequency f1 from the oscillator 45 and an AC signal ofthe frequency f2 from the oscillator 46 are supplied as signals forgenerating a position detecting signal to be transmitted in response toswitching selection of the switch circuit 414 by the control circuit410, and a feedback signal from the feedback signal generation circuit415 is supplied as a position detecting signal to be transmitted. Thefeedback signal generation circuit 415 enhances a signal received fromthe position detection system 2 through the peripheral electrode 6, inthe present example, by amplification and further inverts the phase ofthe signal. An example of a configuration and an example of processingof the feedback signal generation circuit 415 are hereinafter describedin detail. The control circuit 410 generates a switching selectionsignal for the switch circuit 414 on the basis of information based on apen type decision result from the pen type decision circuit 411.

Further, the connection portion between the center electrodetransmission signal generation circuit 412 and the center electrode 7 isconnected to the conductor portion 32 of the housing 3 through theswitch circuit 416. Further, the peripheral electrode 6 is connected tothe conductor portion 32 of the housing 3 through the switch circuit417. Further, the switch circuits 416 and 417 are each switched by anon-off control signal from the control circuit 410. The control circuit410 generates an on-off control signal for each of the switch circuits416 and 417 on the basis of information based on a pen type decisionresult from the pen type decision circuit 411.

The pen type decision circuit 411 is configured from a pen type tablememory 4111 and a decision processing circuit 4112. To the decisionprocessing circuit 4112 of the pen type decision circuit 411,information from the position detection system 2 received by a receptioncircuit (i.e., receiver) 422 of the wireless communication circuit 42 issupplied, and a signal received from the position detection system 2through the peripheral electrode 6 is supplied.

In the pen type table memory 4111, a plurality of configuration types ofthe position indicator 1 and pen type table information regarding, forthe position indicator of each configuration type, whether or not aposition detecting signal is to be transmitted and whether a frequencyof an oscillator for generating the position detecting signal to betransmitted or additional information is to be transmitted from thecenter electrode 7 or is to be transmitted through the wirelesscommunication circuit 42 are stored. While the pen type tableinformation may be stored in the pen type table memory 4111 in advance,in the present example, writing and rewriting can be performed throughthe wireless communication circuit 42 in accordance with a command fromthe position detection system 2.

The decision processing circuit 4112 decides information from theposition detection system 2 received by the reception circuit 422 of thewireless communication circuit 42 or a signal received from the sensorcircuit of the position detection system 2 through the peripheralelectrode 6 and refers to the pen type table information of the pen typetable memory 4111 to decide a configuration type of a position indicatorcompatible with the position detection system 2 to be used together withthe position indicator 1. Then, the decision processing circuit 4112generates, on the basis of a result of the decision, informationregarding whether or not a signal is to be transmitted from the centerelectrode 7, what a position detecting signal and additional informationto be transmitted from the center electrode 7 are and what additionalinformation to be transmitted through the wireless communication circuit42 is, and supplies the generated information to the control circuit410.

The control circuit 410 generates a switching selection signal for theswitch circuit 414 and on-off controlling signals for the switchcircuits 416 and 417 on the basis of the information from the pen typedecision circuit 411 and supplies the generated signals to each of theswitch circuits 414, 416, and 417. Further, the control circuit 410determines additional information to be supplied to the center electrodetransmission signal generation circuit 412 and additional information tobe supplied to the wireless transmission signal generation circuit 413and supplies the determined additional information to each of the centerelectrode transmission signal generation circuit 412 and the wirelesstransmission signal generation circuit 413.

FIG. 5 illustrates an example of the pen type table information of thepen type decision circuit 411. The example of FIG. 5 is tableinformation regarding five different position indicators of theconfiguration type 1 to configuration type 5 (mode 1 to mode 5). The pentype decision circuit 411 refers, after it decides a configuration type(mode) of a position indicator, to the pen type table information togenerate control information to be supplied to the control circuit 410.In the following, it is described that, in the position indicator 1 ofthe present embodiment, each configuration type (mode) is switchablyconfigured under the control of the control circuit 410.

The configuration type 1 (mode 1) is a position indicator of the passivescheme, and does not transmit a signal from the center electrode 7 whileall additional information is transmitted through the wirelesscommunication circuit 42. In particular, in the signal transmissioncontrol circuit 41 of the position indicator 1, if the pen type decisioncircuit 411 decides the configuration of the position indicator 1 is tobe of type 1 (mode 1), then the control circuit 410 switches on theswitch circuits 416 and 417 and places the center electrode transmissionsignal generation circuit 412 into an inoperative state. The switchcircuit 417 may otherwise be off. Then, the control circuit 410 controlssuch that all additional information is transmitted to the positiondetection system 2 through the wireless transmission signal generationcircuit 413 and through the transmission circuit 421 of the wirelesscommunication circuit 42. It is to be noted that the identificationinformation may not have to be transmitted as additional information.

The configuration type 2 (mode 2) is a position indicator of theimproved type of the passive scheme. If the pen type decision circuit411 decides the configuration of the position indicator 1 is to be oftype 2 (mode 2), then on the basis of the information from the pen typedecision circuit 411, the control circuit 410 switches off the switchcircuits 416 and 417 and further switches the switch circuit 414 into astate in which a signal from the feedback signal generation circuit 415is selected. Then, control is performed by the control circuit 410 totransmit all additional information from the position detection system 2through the wireless transmission signal generation circuit 413 andthrough the transmission circuit 421 of the wireless communicationcircuit 42. It is to be noted that the identification information maynot be transmitted as the additional information.

The configuration type 3 (mode 3) is a first type of a positionindicator of the active scheme. If the pen type decision circuit 411decides the configuration of the position indicator 1 is to be of type 3(mode 3), then on the basis of the information from the pen typedecision circuit 411, the control circuit 410 switches off the switchcircuit 416 and switches on the switch circuit 417 and further switchesthe switch circuit 414, in the present example, into a state in which anAC signal from the oscillator 45 of the frequency f1 is selected. Then,control is performed by the control circuit 410 to transmit alladditional information to the position detection system 2 through thewireless transmission signal generation circuit 413 and through thetransmission circuit 421 of the wireless communication circuit 42. It isto be noted that the identification information may not be transmittedas the additional information.

The configuration type 4 (mode 4) is a second type of a positionindicator of the active scheme. If the pen type decision circuit 411decides the configuration of the position indicator 1 is to be of type 4(mode 4), then on the basis of the information from the pen typedecision circuit 411, the control circuit 410 switches off the switchcircuit 416 and switches on the 417 and further switches the switchcircuit 414, in the present example, into a state in which an AC signalfrom the oscillator 46 of the frequency f2 is selected. Then, control isperformed by the control circuit 410 to transmit the writing pressureinformation and the side switch information from within the additionalinformation out together with a position detecting signal from thecenter electrode 7, and control is performed by the control circuit 410to transmit the identification information ID to the position detectionsystem 2 through the wireless transmission signal generation circuit 413and through the transmission circuit 421 of the wireless communicationcircuit 42.

The configuration type 5 (mode 5) is a third type of a positionindicator of the active scheme. If the pen type decision circuit 411decides the configuration of the position indicator 1 is to be of type 5(mode 5), then on the basis of the information from the pen typedecision circuit 411, the control circuit 410 switches off the switchcircuit 416 and switches on the switch circuit 417 and further switchesthe switch circuit 414, in the present example, into a state in which anAC signal from the oscillator 46 of the frequency f2 is to be selected.Then, control is performed by the control circuit 410 to transmit all ofthe additional information from the center electrode 7 together with theposition detecting signal.

In this manner, the signal transmission control circuit 41 decides aconfiguration type of a position indicator on the basis of informationand signals received from the sensor circuit of the position detectionsystem 2 through the reception circuit 422 of the wireless communicationcircuit 42 and the peripheral electrode 6 and configures the positionindicator 1 as a position indicator of the decided configuration type.Accordingly, the position indicator 1 of the present embodiment canautomatically configure and use position indicators of the variousconfiguration types compatible with a plurality of position detectionsystems 2 of various schemes. In other words, position indication inputcan be performed only by the position indicator 1 of the presentembodiment for a plurality of position detection systems 2 of variousschemes. Therefore, there is no necessity to prepare a positionindicator for each of a plurality of position detection systems 2 ofvarious schemes, which is very convenient, and also the burden on theuser in terms of cost is reduced.

It is to be noted that the pen type information from the positiondetection systems 2 received through the wireless communication circuit42 is not limited to information of a configuration type by which eachof the configuration types 1 to 5 is identified directly, but may beinformation which indirectly indicates the numbers of the configurationtypes 1 to 5 of the pen type table information, addresses of theconfiguration types of the pen type table memory 4111 and so forth.

It is to be noted that, in FIG. 4, it is also possible for the controlcircuit 410 to configure the processing functions of the decisionprocessing circuit 4112 of the pen type decision circuit 411, the centerelectrode transmission signal generation circuit 412 and the wirelesstransmission signal generation circuit 413 as software. This similarlyapplies also to the feedback signal generation circuit 415.

Example of Processing Operations of Signal Transmission Control Circuit41

Now, an example of processing operations performed by the signaltransmission control circuit 41 after the power supply switch 48 isswitched on is described with reference to flow charts of FIGS. 6 and 7.

The signal transmission control circuit 41 first decides whether or notinformation is received by the reception circuit 422 of the wirelesscommunication circuit 42 (S1), and if it is decided that information isreceived, then the signal transmission control circuit 41 decideswhether or not the received information is pen type information (S2). Ifit is decided at S2 that the received information is pen typeinformation, then the signal transmission control circuit 41 decides aconfiguration type (pen type) of the position indicator on the basis ofthe received pen type information and refers to the pen type tablememory 4111 to determine signals to be transmitted from the centerelectrode 7 and the transmission receiver 421 of the wirelesscommunication circuit 42 (S3). This determination includes adetermination of whether or not a position detecting signal is to betransmitted from the center electrode 7 as described hereinabove.

Next, the signal transmission control circuit 41 performs control totransmit a signal out in accordance with the configuration type decidedat S3 through the center electrode 7 and the transmission circuit 421 ofthe wireless communication circuit 42 (step S4).

Then, the signal transmission control circuit 41 decides whether or notit has become impossible to receive information from the positiondetection system 2 through the reception circuit 422 of the wirelesscommunication circuit 42 (S5), and if it is decided that it has notbecome impossible to receive information, then the signal transmissioncontrol circuit 41 returns the processing at S4 to continue the signaltransmission in accordance with the decided configuration type.

If it is decided at S5 that it has become impossible to receiveinformation from the position detection system 2 through the receptioncircuit 422 of the wireless communication circuit 42, then the signaltransmission control circuit 41 decides whether or not a predeterminedperiod of time or longer elapses after it has become impossible toreceive information (S6). If it is decided at S6 that the predeterminedperiod of time or longer does not elapse, then the signal transmissioncontrol circuit 41 returns to S4 and sends the signal in accordance withthe decided configuration type.

If it is decided at S6 that the predetermined period of time or longerhas elapsed, then the signal transmission control circuit 41 pauses thesignal transmission from the center electrode 7 and the transmissioncircuit 421 of the wireless communication circuit 42 and places theposition indicator 1 into a sleep state (S7). In this sleep state, inorder to reduce exhaustion of the battery 5 as far as possible toachieve power savings, although supply of power to the reception circuit422 of the wireless communication circuit 42 and the control circuit 410and pen type decision circuit 411 of the signal transmission controlcircuit 41 is maintained, wasteful power supply to the other componentsis stopped.

Then, the signal transmission control circuit 41 returns to S1 andrepeats the processing operations described above.

When it is decided at S1 that information is not received by thereception circuit 422 of the wireless communication circuit 42, or whenit is decided at S2 that the received information is not pen typeinformation, the signal transmission control circuit 41 decides whetheror not a signal is received through the peripheral electrode 6 (S11 ofFIG. 7). If it is decided at S11 that a signal is not received throughthe peripheral electrode 6, then the signal transmission control circuit41 switches on the switch circuit 416 to connect the center electrode 7to the grounding conductor (ground) of the printed wiring board 40through the conductor portion 32 to establish a state of theconfiguration type 1 (S18). Then, the signal transmission controlcircuit 41 returns the processing to S1 of FIG. 6 and repeats theprocessing operations described above beginning at S1.

If it is decided at S11 that a signal is received through the peripheralelectrode 6, then it is decided whether or not it is possible to decidea pen type from the received signal (S12). If it is decided at step thatit is not possible to decide a pen type, then the signal transmissioncontrol circuit 41 switches on the switch circuit 416 to connect thecenter electrode 7 to the grounding conductor (ground) of the printedwiring board 40 through the conductor portion 32 to establish a state ofthe configuration type 1 (S18). Then, the signal transmission controlcircuit 41 returns to S1 of FIG. 6 and repeats the processing operationsbeginning with S1.

If it is decided at S12 that it is possible to decide a pen type, thenthe signal transmission control circuit 41 decides a configuration type(pen type) of the position indicator on the basis of the received signaland refers to the pen type table memory 4111 to determine signals to betransmitted from the center electrode 7 and the transmission circuittransmitter 421 of the wireless communication circuit 42 (S13). Thisdetermination includes a determination of whether or not a positiondetecting signal is to be transmitted from the center electrode 7 asdescribed hereinabove.

Next, the signal transmission control circuit 41 performs control totransmit the signal out in accordance with the configuration typedecided at S13 through the center electrode 7 and the transmissioncircuit 421 of the wireless communication circuit 42 (S14).

Then, the signal transmission control circuit 41 decides whether or notit has become impossible to receive a signal through the peripheralelectrode 6 (S15), and if it is decided that it has not becomeimpossible to receive a signal through the peripheral electrode 6, thenthe signal transmission control circuit 41 returns the processing to S14and continues the signal transmission in accordance with the decidedconfiguration type.

If it is decided at S15 that it has become impossible to receive asignal through the peripheral electrode 6, then the signal transmissioncontrol circuit 41 decides whether or not a predetermined period of timeor longer elapses (S16). If it is decided at S16 that the predeterminedperiod of time or longer does not elapse, then the signal transmissioncontrol circuit 41 returns the processing to S14 and continues thesignal transmission in accordance with the decided configuration type.

If it is decided at S16 that the predetermined period of time or longerelapses, then the signal transmission control circuit 41 pauses thesignal transmission from the center electrode 7 and the transmissioncircuit 421 of the wireless communication circuit 42 and places theposition indicator 1 into a sleep state (S17). Then, the signaltransmission control circuit 41 returns the processing to S1 and repeatsthe processing operations beginning with S1, as described hereinabove.

[Description of Operation of Position Indicators of VariousConfiguration Types and Compatible Position Detection Systems]

<Position Indicator 1A of Configuration Type 2 and Compatible PositionDetection System 2A>

FIG. 8 is a view depicting an example of a circuit of a principalportion of the position indicator 1A of the configuration type 2 andparticularly depicting an example of a circuit configuration of afeedback signal generation circuit 415 and an example of a circuitconfiguration of a power supply circuit 50 whose description is omittedabove.

The power supply circuit 50 includes a DC/DC (Direct Current-DirectCurrent) converter 501 and generates a power supply voltage+Vcc from avoltage of the battery 5 and supplies the power supply voltage+Vcc tothe signal transmission control circuit 41 and other components.

Further, in the power supply circuit 50, a power supply switch 48 isprovided between the DC/DC converter 501 and the battery 5. Further, aseries circuit of a resistor 502 and an LED 49 is connected between anoutput terminal of the DC/DC converter 501 and a grounding conductor.Furthermore, an output terminal of the DC/DC converter 501 is connectedto a grounding conductor through a series connection of a resistor 503and another resistor 504, and a reference voltage Vref (=Vcc/2, forexample) is outputted from the connection point between the resistor 503and the resistor 504.

The feedback signal generation circuit 415 is configured, in the presentexample, as a signal enhancement processing circuit and is configuredfrom a sense amplifier 510, a signal amplification factor variationcircuit 520 and a transformer 530.

In the present example, the sense amplifier 510 is configured from anoperational amplifier 511, and a capacitor 512 connected between aninverting input terminal and an output terminal of the operationalamplifier 511. The inverting input terminal of the operational amplifier511 is connected to a connection terminal 513 connected to theperipheral electrode 6. Further, the reference voltage Vref describedhereinabove is supplied to a non-inverting input terminal of theoperational amplifier 511.

When the position indicator 1A is on the position detection system 2A,the peripheral electrode 6 of the position indicator 1A and the positiondetection system 2A are coupled to each other through a capacitance C1as depicted in FIG. 1. Since an AC signal flows in the positiondetection system 2A as hereinafter described, this AC signal is suppliedas a current signal to the connection terminal 513 through thecapacitance C1 and the peripheral electrode 6 and inputted to the senseamplifier 510. The capacitor 512 is provided to detect the currentsignal inputted thereto through the capacitance C1.

Then, the sense amplifier 510 inverts the phase of the AC signalinputted as a current signal through the connection terminal 513 andoutputs the inverted phase AC signal to the signal amplification factorvariation circuit 520.

The signal amplification factor variation circuit 520 is configured froman operational amplifier 521, and a variable resistor 522 connectedbetween an inverting input terminal and an output terminal of theoperational amplifier 521. By variably setting the resistance value ofthe variable resistor 522, the amplification factor of the signalamplification factor variation circuit 520 is variably set, and as aresult, the signal detection sensitivity of the position indicator 1A iscontrolled.

The AC signal amplified by the signal amplification factor variationcircuit 520 is supplied to a primary winding 530 a of the transformer530. The ratio between the number of winding n1 of the primary winding530 a and the number of winding n2 of a secondary winding 530 b of thetransformer 530 is set such that the number of windings on the secondarywinding 530 b side is greater like, for example, n1:n2=1:10 (n1<n2).Accordingly, on the secondary winding 530 b side of the transformer 530,the output signal of the signal amplification factor variation circuit520 has an amplitude multiplied in accordance with the winding numberratio, and an AC signal (voltage signal) of the increased amplitude isobtained.

The secondary winding 530 b of the transformer 530 is connected at oneend thereof to a connection terminal 523 connected to the core member 71configured from a bar-like conductor of the center electrode 7 shieldedby the shield member 8, and is connected at the other end thereof to agrounding conductor of the printed wiring board 40. Accordingly, anoutput signal formed as an AC signal voltage of a great amplitude by thefeedback signal generation circuit 415 is supplied to the centerelectrode 7 through the connection terminal 523.

When the position indicator 1A is on the position detection system 2A,since the center electrode 7 of the position indicator 1A and theposition detection system 2A are coupled to each other by a capacitance,an AC signal is fed back from the position indicator 1A to the positiondetection system 2A through the center electrode 7 of the positionindicator 1A.

Now, the position detection system 2A of the present example isdescribed with reference to FIG. 9. The position detection system 2A ofthe present example is configured as a position detection system of themutual capacitance scheme wherein sensor electrodes are configured froman input electrode and an output electrode and a variation of thecoupling capacitance with a touch point at which the position indicator1A touches is detected.

As depicted in FIG. 9, the position detection system 2A of the presentexample includes a sensor 20A, a transmission circuit 21, a receptioncircuit 22, a wireless communication circuit 25, and a control circuit220A. The sensor 20A includes a plurality of, in the present example, m,linear transmission conductors 23Y₁, 23Y₂, . . . , 23Y_(m) (m is aninteger equal to or greater than 1) extending in a transverse direction(X-axis direction) of the sensor inputting face, and a plurality of, inthe present example, n, reception conductors 24X₁, 24X₂, . . . , 24X_(n)(n is an integer equal to or greater than 1) extending in a longitudinaldirection (Y-axis direction) of the sensor inputting face orthogonal tothe transmission conductors 23Y₁ to 23Y_(m). The plurality oftransmission conductors 23Y₁ to 23Y_(m) are disposed at equal distancesin the Y-axis direction and connected to the transmission circuit 21.Meanwhile, the plurality of reception conductors 24X₁ to 24X_(n) aredisposed at equal distances in the X-axis direction and connected to thereception circuit 22.

It is to be noted that, in the explanation of the present descriptiongiven below, where there is no necessity to distinguish the transmissionconductors 23Y₁ to 23Y_(m) from each other and to distinguish thereception conductors 24X₁ to 24X_(n) from each other, each of them isreferred to as transmission conductor 23Y and reception conductor 24X.

The plurality of transmission conductors 23Y and the plurality ofreception conductors 24X are disposed in a spaced relationship by apredetermined distance from each other and have a mutually orthogonaldisposition relationship so as to form a plurality of intersectingpoints (cross points). At each cross point, it can be regarded that atransmission conductor 23Y and a reception conductor 24X are coupled toeach other through a predetermined capacitance.

The transmission circuit 21 supplies a predetermined AC signal to atransmission conductor 23Y under the control of the control circuit220A. In this case, the transmission circuit 21 may supply a same ACsignal to the plurality of transmission conductors 23Y₁, 23Y₂, . . . ,23Y_(m) by successively changing over them one by one or may supply aplurality of AC signals different from each other to the plurality oftransmission conductors 23Y₁, 23Y₂, . . . , 23Y_(m) at the same time.Alternatively, the plurality of transmission conductors 23Y₁, 23Y₂, . .. , 23Y_(m) may be divided into a plurality of groups such that ACsignals different among the different groups may be used.

The reception circuit 22 detects a signal component when an AC signalsupplied to a transmission conductor 23Y is transmitted through thepredetermined capacitance to each of the reception conductors 24X₁,24X₂, . . . , 24X_(n) under the control of the control circuit 220. Ifit is assumed that the coupling capacitance between a transmissionconductor 23Y and a reception conductor 24X is equal at all crosspoints, then when the position indicator 1A is not on the sensor 20A, areception signal of a predetermined level is detected by the receptioncircuit 22 from all of the reception conductors 24X₁, 24X₂, . . . ,24X_(n) of the sensor circuit 20A.

In contrast, if the position indicator 1A contacts the sensor 20A, thena transmission conductor 23Y and a reception conductor 24X whichconfigure the cross point at the contact position and the positionindicator 1A are coupled to each other through the capacitance. In otherwords, the capacitance is varied by the position indicator 1A, and thereception signal level obtained from the reception conductor 24X at thecross point at which the position indicator 1A exists exhibits avariation in comparison with the reception signal level at the othercross points.

The reception circuit 22 detects, from among the plurality of thereception conductors 24X₁, 24X₂, . . . , 24X_(n), a reception conductor24X which exhibits a variation of the level of the reception signal todetect the indication position by the position indicator 1A. Then, thecontrol circuit of the position detection system 2A which is notdepicted in FIG. 9 detects the transmission conductor 23Y to which theAC signal is supplied from the transmission circuit 21 and the receptionconductor 24X whose variation in reception signal level is detected bythe reception circuit 22 to detect the cross point with which theposition indicator 1A contacts.

Also when not the position indicator 1A but a finger comes close to orcontacts the sensor 20A, the position detection system 2A detects across point close to or contacted by the finger in accordance with asimilar principle. In this case, part of the AC signal supplied to thetransmission conductor 23Y flows to the ground through the finger andfurther through the human body of the user. Therefore, the receptionsignal level of the reception conductor 24X which configures the crosspoint at which the finger exists varies. The reception circuit 22detects the variation of the reception signal level to detect thereception conductor 24X which configures the cross point at which thefinger exists.

Where the position indicator is of the configuration type 1, theposition detection system 2A can perform detection of an indicationposition on the sensor 20A similarly in accordance with the principle ofposition detection of a finger. However, in the case of the positionindicator of the configuration type 1, since the contact area of theposition indicator with the position detection system 2A is not as greatas that of a finger with the position detection system 2A, the couplingcapacitance is low and the position detection system 2A indicates alower detection sensitivity. Therefore, the position detection systemcompatible with the position indicator of the configuration type 1compensates for the detection sensitivity against the decrease by takinga correlation of a transmission signal and a reception signal using aspread code as an AC signal to be transmitted to the position indicatoror taking a like means to detect the indication position of the positionindicator.

In contrast, in the case of the position indicator 1A of theconfiguration type 2 and the position detection system 2A, even if aspread code or the like is not used, the affinity between the positionindicator 1A and the position detection system 2A is high and besidesthe versatility of them is high. Furthermore, a predetermined waveformcorrelation is secured between an input signal and an output signal andposition detection on the sensor 20A can be achieved with a highsensitivity.

In particular, when the position indicator 1A is moved close to orbrought into contact with the sensor 20A of the position detectionsystem 2A, the AC signal supplied to a transmission conductor 23Y isinputted to the feedback signal generation circuit 415 through thecapacitance C1 as depicted in FIG. 1 and through the peripheralelectrode 6 and as a current signal further through the connectionterminal 513.

The AC signal (current signal) inputted to the feedback signalgeneration circuit 415 is inverted in phase by the sense amplifier 510and amplified by the signal amplification factor variation circuit 520,and is further boosted (multiplied) into an enhanced signal by thetransformer 530 and supplied as a voltage signal to the center electrode7 through the connection terminal 523. In particular, the AC signalinputted from the sensor 20A to the feedback signal generation circuit415 through the peripheral electrode 6 is inverted in phase and enhancedinto a signal of an increased amplitude in the feedback signalgeneration circuit 415, and then fed back to the sensor 20A through thecenter electrode 7.

In this case, since the AC signal fed back from the center electrode 7of the position indicator 1A to the sensor 20A of the position detectionsystem 2A is a signal of an inverted phase enhanced from the AC signalsupplied to the transmission conductor 23Y, the position indicator 1Afunctions to further increase the variation of the AC signal of thereception signal of the reception conductor 24X. Therefore, the positiondetection system 2A can detect the contact position of the positionindicator 1A with a high sensitivity. It is to be noted that, where thegrounding conductor of the position indicator 1A is connected to thehuman body, the detection action is further stabilized. In particular,in the present embodiment, the housing 3 of the position indicator 1A iscovered with the conductor portion 32 connected to a grounding conductorof the printed wiring board 40. Therefore, the AC signal supplied to thetransmission conductor 23Y in the position detection system 2A flows tothe ground through the position indicator 1A and further through thehuman body of the user, and consequently, further stabilization of thesignal detection action can be anticipated.

Further, where the voltage at the transmission conductor 23Y of thesensor 20A of the position detection system 2A is represented by V, thevoltage at the center electrode 7 of the position indicator 1 of thepresent embodiment is represented by e and the capacitance between theperipheral electrode 6 and the center electrode 7 is represented by C2(refer to FIG. 1), they have a relationship of

e≦C1/C2·V

Therefore, in order to make the voltage e of the center electrode 7high, it is advantageous to decrease the capacitance C2 between theperipheral electrode 6 and the center electrode 7 as far as possible.

To this end, in the position indicator 1 of the present embodiment, theshield member 8 is interposed between the peripheral electrode 6 and thecenter electrode 7 to decrease the coupling between them as far aspossible. Accordingly, in the position indicator 1 of the presentembodiment, the capacitance C2 between the peripheral electrode 6 andthe center electrode 7 is decreased by interposing the shield member 8between them, and the voltage e can be made higher and the sensitivitycan be increased efficiently.

The position indicator 1 of the embodiment described above is configuredsuch that the peripheral electrode 6 receives an AC signal from theposition detection system 2A and an enhanced output AC signal is fedback from the center electrode 7 to the position detection system 2A.However, the electrode for receiving an AC signal from the positiondetection system 2A may be the center electrode 7 while the electrodefor feeding back an enhanced AC signal to the position detection system2A may be the peripheral electrode 6.

It is to be noted that, as depicted in FIG. 9, in the position indicator1A of the configuration type 2, writing pressure information, sideswitch information and identification information are wirelesslytransmitted from the wireless communication circuit 42 to the wirelesscommunication circuit 25 of the position detection system 2A. Thewriting pressure information, side switch information and identificationinformation received by the wireless communication circuit 25 aresupplied to the control circuit 220A and transmitted, for example, to ahost computer together with the detected position information. Also,additional information from the position indicator of the configurationtype 1 is transmitted from the wireless communication circuit 42 to theposition detection system in a similar manner.

<Position Indicator 1B of Configuration Type 3 and Compatible PositionDetection System 2B>

FIG. 10 is a view depicting an example of a circuit of a principalportion of a position indicator 1B of the configuration type 3 and acompatible position detection system 2B. The position indicator 1B ofthe configuration type 3 transmits an AC signal of a frequency f1 as aposition detecting signal and transmits all of writing pressureinformation, side switch information and identification information,which are additional information, from a wireless communication circuit42 to a wireless communication circuit 25B of the position detectionsystem 2B.

As depicted in FIG. 10, the position detection system 2B is configuredfrom a sensor 20B, a pen indication detection circuit 26B connected tothe sensor 20B, and the wireless communication circuit 25B.

The sensor 20B is configured by stacking a first conductor group 211, aninsulating layer (not depicted) and a second conductor group 212 inorder from the lower layer side. The first conductor group 211 includesa plurality of first conductors 211Y₁, 211Y₂, . . . , 211Y_(m) (m is aninteger equal to or greater than 1) extending in a transverse direction(X-axis direction) and disposed in parallel to each other in a Y-axisdirection in a spaced relationship by a predetermined distance from eachother.

Meanwhile, the second conductor group 212 includes a plurality of secondconductors 212X₁, 212X₂, . . . , 212X_(n) (n is an integer equal to orgreater than 1) extending in a direction crossing with the extendingdirection of the first conductors 211Y₁, 211Y₂, . . . , 211Y_(m), in thepresent example, in a longitudinal direction (Y-axis direction)orthogonal to the extending direction of the first conductors 211Y₁,211Y₂, . . . , 211Y_(m), and disposed in parallel to each other in theX-axis direction in a spaced relationship by a predetermined distancefrom each other.

It is to be noted that, in the following description, where there is nonecessity to distinguish the first conductors 211Y₁, 211Y₂, . . . ,211Y_(m) from each other, each of the conductors is referred to as firstconductor 211Y. Similarly, where there is no necessity to distinguishthe second conductors 212X₁, 212X₂, . . . , 212X_(n) from each other,each of the conductors is referred to as second conductor 212X.

The pen indication detection circuit 26B is configured from a selectioncircuit 221 serving as an input/output interface with the sensor circuit20B, an amplification circuit 222, a band pass filter 223B, a detectioncircuit 224, a sample and hold circuit 225, an AD (Analog to Digital)conversion circuit 226, and a control circuit 220B.

The selection circuit 221 selects one conductor from each of the firstconductors 211Y and the second conductors 212X in accordance with acontrol signal from the control circuit 220B. Each of the conductorsselected by the selection circuit 221 is connected to the amplificationcircuit 222 such that a signal from the position indicator 1B isdetected by the selected conductor and amplified by the amplificationcircuit 222. An output of the amplification circuit 222 is supplied tothe band pass filter 223B, by which only a component of the frequency f1is extracted from the signal transmitted from the position indicator 1B.

The output signal of the band pass filter 223B is detected by thedetection circuit 224. An output signal of the detection circuit 224 issupplied to the sample and hold circuit 225, and a sample thereof isheld at a predetermined timing in response to a sampling signal from thecontrol circuit 220B by the sample and hold circuit 225 and thenconverted into a digital value by the AD conversion circuit 226. Thedigital data from the AD conversion circuit 226 is read and processed bythe control circuit 220B.

The control circuit 220B operates to transmit control signals to thesample and hold circuit 225, AD conversion circuit 226 and selectioncircuit 221 in accordance with a program stored in an internal ROM (ReadOnly Memory). Further, the control circuit 220B calculates a positionalcoordinate on the sensor 20B indicated by the position indicator 1B fromthe digital data from the AD conversion circuit 226.

FIG. 11 is a timing chart illustrating a signal transmitted from theposition indicator 1B of the configuration type 3 to the compatibleposition detection system 2B. As described above, for example, a signalbased on an AC signal of the frequency f1 is transmitted successively asa position detecting signal from the position indicator 1B of theconfiguration type 3 through the center electrode 7.

However, in the position indicator 1B of the configuration type 3 of thepresent example, making use of an advantage that the position indicator1 of the embodiment can send out an AC signal of the frequency f1 andanother AC signal of the frequency f2 as position detecting signals, thefrequency of the position detecting signal can be switched when noise ofa frequency equal to that of the position detecting signal exists.

In particular, in the position indicator 1B of the configuration type 3in the embodiment, as depicted in the upper portion of FIG. 11, theposition detecting signal is configured such that one cycle configuredfrom a continuous transmission period having a predetermined periodlength Ta and a pause period having another predetermined period lengthTb is repeated.

In the control circuit 220B of the position detection system 2B, asdepicted in FIG. 11 (second from top), using the pause period of thepredetermined period length Tb as a window interval for detectingpresence or absence of noise, it is detected within the window intervalwhether or not there exists noise of a frequency equal to that of theposition detecting signal. If it is detected within the window intervalthat there exists noise of a frequency equal to that of the positiondetecting signal, then the control circuit 220B of the positiondetection system 2B issues a notification of this to the positionindicator 1B through the wireless communication circuit 25B.

If the notification is received from the position detection system 2B,then the reception circuit 422 of the wireless communication circuit 42of the position indicator 1B transfers the received notification to thecontrol circuit 410 of the signal transmission control circuit 41. Thecontrol circuit 410 of the signal transmission control circuit 41performs switching control of the switch circuit 414 in accordance withthe notification to perform switching from a state in which theoscillator 45 of the frequency f1 is selected to another state in whichthe oscillator 46 of the frequency f2 is selected. It is to be notedthat, where the position detecting signal from the position indicator 1Bwhen the notification from the position detection system 2B is receivedis based on a signal from the oscillator 46 of the frequency f2, inaccordance with the notification from the position detection system 2B,the control circuit 410 performs switching control of the switch circuit414 thereby to perform switching from the state in which the oscillator46 of the frequency f2 is selected to the state in which the oscillator45 of the frequency f1 is selected.

For example, when the position detecting signal from the positionindicator 1B is a signal of the frequency f1 as depicted in FIG. 11, ifnoise NR at a frequency equal to the frequency f1 exists as depicted inFIG. 11, then the control circuit 220B of the position detection system2B detects the noise NR within the window interval depicted in FIG. 11and sends the result of the detection to the position indicator 1Bthrough the wireless communication circuit 25B.

In the position indicator 1B, the control circuit 410 receives thenotification from the position detection system 2B through the receptioncircuit 422 of the wireless communication circuit 42 and performsswitching control of the switch circuit 414 such that the frequency ofthe position detecting signal is switched from the frequency f1 to thefrequency f2 as depicted in the lower portion of FIG. 11. Accordingly,even if noise of a frequency equal to that of the position detectingsignal exists around the position detection system 2B, the influence ofthe noise can be eliminated by the switching of the frequency of theposition detecting signal.

It is to be noted that, in the position detection system 2B, the bandpass filter 223B has a state in which the pass frequency band has thecenter frequency at the frequency f1 and another state in which the passfrequency band has the center frequency at the frequency f2 such thatthe position detection system 2B can deal with both of positiondetecting signals of the frequency f1 and the frequency f2. Further, theposition detection system 2B is configured such that it can switchablydetermine which one of the pass frequency bands is to be used under thecontrol of the control circuit 220B.

<Position Indicator 1C of Configuration Type 4 and Compatible PositionDetection System 2C>

FIG. 12 is a view depicting an example of a circuit of a principalportion of a position indicator 1C of the configuration type 4 and acompatible position detection system 2C. The position indicator 1C ofthe configuration type 4 transmits an AC signal of the frequency f2 as aposition detecting signal and transmits writing pressure information andside switch information, which are examples of important additionalinformation to the position indicator, to the position detection system2C through the center electrode 7 together with the position detectingsignal. The position indicator 1C transmits identification informationof additional information from the wireless communication circuit 42 toa wireless communication circuit 25C of the position detection system2C.

As depicted in FIG. 12, the position detection system 2C is configuredfrom a sensor 20C, a pen indication detection circuit 26C connected tothe sensor 20C, and the wireless communication circuit 25C. In thepresent example, the sensor 20C has a configuration same as that of thesensor 20B of the position detection system 2B. Further, the penindication detection circuit 26C has a configuration that is the same asthat of the pen indication detection circuit 26B except theconfiguration of a band pass filter 223C and a control circuit 220C.

In the present example, the band pass filter 223C of the positionindicator 1C of the configuration type 4 has a pass frequency bandhaving the center frequency at the frequency f2. Further, the controlcircuit 220C has a function for detecting writing pressure informationand side switch information to be sent together with a positiondetecting signal.

In the position indicator 1C of the configuration 4 of the presentexample, a center electrode transmission signal generation circuit 412repetitively outputs a signal of a pattern in which one cycle isconfigured from a continuous transmission period and a transmission dataperiod under the control of the control circuit 410. The upper portionof FIG. 13 depicts an example of a control signal supplied from thecontrol circuit 410 of the position indicator 1C to the center electrodetransmission signal generation circuit 412. The center electrodetransmission signal generation circuit 412 successively transmits anoscillation signal of the frequency f2 as a burst signal as depicted inthe middle portion of FIG. 13 within a fixed period within which a highlevel of the control signal of FIG. 13 is maintained (continuoustransmission period in the lower portion of FIG. 13).

The length of the continuous transmission period is set to a time lengthwithin which an indication position on the sensor circuit 20C by theposition indicator 1C can be detected by the pen indication detectioncircuit 26C of the position detection system 2C, and is set to a timelength within which, for example, all of the first conductors 211Y andthe second conductors 212X can be scanned by one or more times,preferably, by a plural number of times.

Within the continuous transmission period, the control circuit 410 ofthe position indicator 1C calculates a writing pressure applied to thecenter electrode 7 on the basis of the capacitance of the variablecapacitor of the writing pressure detection circuit 9 and determinesinformation of the calculated writing pressure value as a value of aplurality of bits (binary code). Further, the control circuit 410generates on-off information of the side switch 43 as side switchinformation and as information of one bit or a plurality of bits.

Further, as depicted in the upper portion of FIG. 13, the controlcircuit 410 controls, after the continuous transmission period comes toan end, a control signal to the high level or the low level in apredetermined cycle (Td) within the transmission data period to performASK (Amplitude Shift Keying) modulation for the AC signal of thefrequency f2. Alternatively, an OOK (On Off Keying) signal may be usedin place of an ASK modulation signal.

At this time, within the first time predetermined cycle (Td) after thecontinuous transmission period, the control signal is controlled to thehigh level, and the control signal of the high level is used as a startsignal in the lower portion of FIG. 13. The start signal is a timingsignal used to make it possible for the pen indication detection circuit26C of the position detection system 2C to accurately decide a laterdata transmission timing. It is to be noted that also a burst signalwithin the continuous transmission period can be utilized as a timingsignal in place of the start signal.

The center electrode transmission signal generation circuit 412 of theposition indicator 1C is controlled in such a manner as described aboveby the control circuit 410 to successively transmit, within thetransmission data period, writing pressure information of a plurality ofbits and side switch information of one or a plurality of bits followingthe start signal. In this case, as depicted in the upper and middleportions of FIG. 13, when transmission data (binary code) is “0,” thecontrol signal (upper portion of FIG. 13) is controlled to the low levelsuch that transmission of an AC signal is not performed, but, when thetransmission data (binary code) is “1,” the control signal is controlledto the high level such that the AC signal is transmitted to perform ASKmodulation.

In the pen indication detection circuit 26C of the position detectionsystem 2C, the control circuit 220C detects a position indicated by theposition indicator 1C from a reception signal within the continuoustransmission period similarly as in the position detection system 2Bdescribed above. Further, the control circuit 220C waits until an end ofthe continuous transmission period and, if a start signal after the endof the continuous transmission period is detected, then the controlcircuit 220C detects and restores data of the writing pressureinformation and the side switch information within the transmission dataperiod. Then, the control circuit 220C outputs the detection informationof the indication position by the position indicator 1C, the writingpressure information and the side switch information to a host computeror the like together with the identification information receivedthrough the wireless communication circuit 25C.

It is to be noted that the position indicator 1C of the configurationtype 4 may be configured similarly to the position indicator 1B of theconfiguration type 3 such that the frequency of the position detectingsignal is switched so as to reduce the influence of noise. In this case,also the band pass filter 223C and the control circuit 220C of theposition detection system 2C are configured so as to have functionssimilar to those of the band pass filter 223B and the control circuit220B of the position detection system 2B compatible with theconfiguration type 3.

<Position Indicator 1D of Configuration Type 5 and Compatible PositionDetection System 2D>

FIG. 14 is a view depicting an example of a circuit of a principalportion of a position indicator 1D of the configuration type 5 and acompatible position detection system 2D. The position indicator 1D ofthe configuration type 5 transmits an AC signal of the frequency f2 as aposition detecting signal and transmits all additional information, inthe present example, all of writing pressure information, side switchinformation and identification information ID1, to the positiondetection system 2D through the center electrode 7 together with aposition detecting signal.

As depicted in FIG. 14, the position detection system 2D is configuredfrom a sensor 20D, a pen indication detection circuit 26D connected tothe sensor 20D, and a wireless communication circuit 25D. In the presentexample, the sensor 20D has a configuration that is the same as that ofthe sensor 20B of the position detection system 2B. Further, the penindication detection circuit 26D has a configuration that is the same asthat of the pen indication detection circuit 26C including a band passfilter 223D except a control circuit 220D. In particular, in the presentexample, the band pass filter 223D has a pass frequency band having acenter frequency at the frequency f2. The control circuit 220D has afunction for detecting the writing pressure information, side switchinformation and identification information ID1 sent thereto togetherwith the position detecting signal.

Also in the position indicator 1D of the configuration type 5 of thepresent example, the center electrode transmission signal generationcircuit 412 is controlled by the control circuit 410 to repetitivelyoutput a signal of a pattern in which one cycle includes a continuoustransmission period and a transmission data period as depicted in FIG.15 similarly to the position indicator 1C of the configuration type 4.

The upper portion of FIG. 15 illustrates an example of a control signalsupplied from the control circuit 410 of the position indicator 1D tothe center electrode transmission signal generation circuit 412. Thecenter electrode transmission signal generation circuit 412 of theposition indicator 1D of the present example is controlled by thecontrol signal of FIG. 15 to continuously transmit, within thecontinuous transmission period, an oscillation signal of the frequencyf2 as a burst signal as illustrated in the middle portion of FIG. 15 buttransmit, within the transmission data period, the writing pressureinformation, side switch information and identification information ID1as an ASK signal to the position detection system 2D through the centerelectrode 7 as depicted in the middle and lower portions of FIG. 15.

The control circuit 220D of the position detection system 2D detects theposition on the sensor circuit 20D indicated by the position indicator1D on the basis of the burst signal within the continuous transmissionperiod and detects and restores the writing pressure information, sideswitch information and identification information ID1 within thetransmission data period.

Then, in the present example, in order to further secure exchange ofsignals between the position indicator 1D and the position detectionsystem 2D, the position indicator 1D transmits identificationinformation ID2 from the wireless communication circuit 42 to thewireless communication circuit 25D of the position detection system 2D.In this case, the identification information ID1 and the identificationinformation ID2 are made to be the same information (ID1=ID2). Thecontrol circuit 220D compares the identification information ID2acquired through the wireless communication circuit 25D and theidentification information ID1 received and detected through the centerelectrode 7 with each other and processes, only when they coincide witheach other, the signal acquired from the position indicator 1D as avalid signal.

Then, when the control circuit 220D determines that the signal acquiredfrom the position indicator 1D is a valid signal, the control circuit220D outputs the detection information of the indication position by theposition indicator 1D, writing pressure information, side switchinformation and identification information ID1 to the host computer orthe like.

FIG. 16 is a flow chart illustrating a flow of a securing process of thecontrol circuit 220D of the position detection system 2D in which theidentification information ID1 and ID2 is used.

The control circuit 220D temporarily retains the identificationinformation ID2 received through the wireless communication circuit 25D(S21). Then, the control circuit 220D acquires the identificationinformation ID1 included in the information transmitted thereto throughthe center electrode 7 of the position indicator 1D (S22). Then, thecontrol circuit 220D decides whether or not the identificationinformation ID1 and the identification information ID2 coincide witheach other (S23), and if it is decided that the identificationinformation ID1 and the identification information ID2 coincide witheach other, then it processes the signal from the position indicator 1Das a valid signal (S24). Thereafter, the control circuit 220D returnsthe processing to S21 and repeats the processing operations beginning atS21. On the other hand, if it is decided at S23 that the identificationinformation ID1 and the identification information ID2 do not coincidewith each other, then the control circuit 220D processes the signal fromthe position indicator 1D as an invalid signal (S25). Thereafter, thecontrol circuit 220D returns the processing to S21 and repeats theprocessing operations beginning with step S21.

It is to be noted that the securing process which uses comparisonbetween the identification information ID2 from the wirelesscommunication circuit 42 and the identification information ID1 acquiredthrough the center electrode 7 in the position detection system 2D isnot an essentially required process but may not be performed.

Other Embodiments Other Examples of Capacitive Coupling Scheme

The plurality of configuration types of the position indicator describedabove are mere examples, and it is a matter of course that theconfiguration type of the position indicator is not limited to thosedescribed above. For example, while the position indicator of the activescheme described above transmits a signal only from the center electrode7, a position indicator configured such that, in order to make itpossible to detect an inclination angle or a rotational angle of theposition indicator on the position detection system, the peripheralelectrode 6 is divided into a plurality of divisional peripheralelectrodes such that each of the plurality of divisional peripheralelectrodes transmits a signal for making it possible to identify thedivisional peripheral electrodes from each other may be used as aposition indicator of one configuration type.

FIGS. 17A and 17B are views depicting parts of a position indicator 1Ewhich can configure also a position indicator of such a configurationtype as just above, and FIG. 17A is a view illustrating components ofthe center electrode 7 side and FIG. 17B is a view when the positionindicator 1E is viewed in an axial direction from the distal end side ofthe center electrode 7.

In the present position indicator 1E, a peripheral electrode configuredfrom a conductor provided around an opening 3 a of a housing 3 in whichthe center electrode 7 is inserted is provided as three dividedperipheral electrodes 6A, 6B and 6C. The divided peripheral electrodes6A, 6B and 6C are provided in an electrically isolated and separatedrelationship from each other as depicted in FIGS. 17A and 17B.

Further, in the case of the configuration type 1 of the passive schemeand the configuration types 3, 4 and 5 of the active scheme describedhereinabove, the divided peripheral electrodes 6A, 6B and 6C are notused. In the case of the configuration type 2 of the improved type ofthe passive scheme, the divided peripheral electrodes 6A, 6B and 6C areconfigured such that they are electrically connected to each other andsignals received by all of the divided peripheral electrodes 6A, 6B and6C are synthesized and supplied to the feedback signal generationcircuit 415.

Further, where a position indicator of a configuration type whoseinclination angle or rotational angle on a position detection system canbe detected is configured from the position indicator 1E, the positionindicator is configured such that a position detecting signal andadditional information selected in response to a configuration type aretransmitted from the center electrode 7 while signals from which thedivided peripheral electrodes 6A, 6B and 6C can individually be detectedby the position detection system are transmitted from the dividedperipheral electrodes 6A, 6B and 6C.

For example, the position indicator is configured such that, from eachof the divided peripheral electrodes 6A, 6B and 6C, identificationinformation (for example, a signal of 2 bits) corresponding to each ofthe divided peripheral electrodes 6A, 6B and 6C is transmitted or suchthat signals of frequencies or phases different from one another aretransmitted from the divided peripheral electrodes 6A, 6B and 6C.Alternatively, the position indicator is configured such that, aftertransmission of a signal from the center electrode 7 comes to an end, asignal of one frequency is transmitted in order from the dividedperipheral electrodes 6A, 6B and 6C for each predetermined period.

A position detection system compatible with a position indicator of aconfiguration type in which the inclination angle or rotational angle ofthe position indicator on the position detection system can be detectedhas a function for detecting a rotational angle or an inclination angleof the position indicator 1E from a reception intensity of a signal fromeach of the divided peripheral electrodes 6A, 6B and 6C or a spreadingdistribution pattern of a reception signal.

Example of Electromagnetic Coupling Scheme

Further, while the embodiment described above is directed to a positionindicator and a position detection system of the capacitive couplingscheme, the present disclosure can be applied also to a positionindicator and a position detection system of the electromagneticcoupling scheme.

FIG. 18 depicts an example of a configuration of a position indicator100 of the electromagnetic coupling scheme according to the presentdisclosure and corresponds to the view of the conceptual configurationof FIG. 1 which depicts the position indicator 1 of the embodimentdescribed hereinabove.

As depicted in FIG. 18, the position indicator 100 of the presentembodiment includes a signal transmission control circuit 141, awireless communication circuit 142, a side switch 143, an ID memory 144and an oscillator 145 in a tubular housing 103 made of an insulator suchas a resin and further includes a writing pressure detection circuit109. Further, a battery 105 is provided as a supply source of a powersupply voltage to the signal transmission control circuit 141, wirelesscommunication circuit 142, side switch 143, ID memory 144, oscillator145 and so forth in the housing 103. The signal transmission controlcircuit 141 includes a pen type decision circuit 1411.

Further, a core member 107 extending through a ferrite core 110 iscoupled to the writing pressure detection circuit 109 such that thewriting pressure detection circuit 109 detects a writing pressureapplied to the core member 107 as a capacitance of a variable capacitorconfigured from the writing pressure detection circuit 109. The ferritecore 110 has a coil 111 wound thereon, and the coil 111 is connected atthe opposite ends thereof to the signal transmission control circuit141. Further, a capacitor 112 cooperating with the coil 111 to configurea resonance circuit is connected between the opposite ends of the coil111.

To the signal transmission control circuit 141, the wirelesscommunication circuit 142, side switch 143, ID memory 144 and oscillator145 are connected similarly as in the position indicator 1 of theembodiment described above, and also the variable capacitor configuredfrom the writing pressure detection circuit 109 is connected to thesignal transmission control circuit 141.

The signal transmission control circuit 141 selectively controls, in thepresent position indicator 100, a signal to be transmitted through theresonance circuit including the coil 111 and the capacitor 112 andselectively controls whether additional information such as writingpressure information, side switch information and identificationinformation is to be transmitted from the wireless communication circuit142 or transmitted as a signal from the resonance circuit.

In particular, in the case of the position indicator 100 of the presentembodiment, the resonance circuit configures a first transmissioncircuit (first transmitter) and a transmission circuit of the wirelesscommunication circuit 142 configures a second transmission circuit(second transmitter). Further, a reception circuit of the wirelesscommunication circuit 142 configures a reception circuit (receiver)which receives pen type information from the position detection system.Pen type information received from the position detection system by thereception circuit of the wireless communication circuit 142 is suppliedto the pen type decision circuit 1411 of the signal transmission controlcircuit 141. Though not depicted, also in the present embodiment, thepen type decision circuit 1411 can be configured from a decisionprocessing circuit of a pen type and a pen type table memory.

The signal transmission control circuit 141 of the position indicator100 of the present embodiment receives pen type information from theposition detection system, and the pen type decision circuit 1411decides and determines a pen type and can configure, for example, suchposition indicators 100A, 100B and 100C of three different configurationtypes 6, 7 and 8 as depicted in FIGS. 19A, 19B and 19C, respectively.

If pen type information received from the position detection systemthrough the reception circuit of the wireless communication circuit 142of the position indicator 100 is the configuration type 6, then such aposition indicator 100A as depicted in FIG. 19A is configured by thesignal transmission control circuit 141. In particular, in the presentconfiguration type 6, a variable capacitor configured from the writingpressure detection circuit 109 is connected in parallel to the parallelresonance circuit configured from the coil 111 and the capacitor 112,and further, a series circuit of the side switch 143 and a capacitor 113is connected to the resonance circuit.

Further, the sensor circuit of a position detection system 200A which isused together with the position indicator 100A of the configuration type6 and sends the configuration type 6 as pen type information to theposition indicator 100A is configured, though not depicted, such thatpluralities of loop coils are arrayed in an X direction and a Ydirection which are orthogonal to each other such that a transmissionsignal (AC signal) of a frequency fa is transmitted from a loop coil tothe position indicator 100A.

In the position indicator 100A, an AC signal from the position detectionsystem 200A is received by the resonance circuit through electromagneticcoupling and then the AC signal is fed back from the resonance circuitto the position detection system 200A. In the position detection system200A, the position indicated by the position indicator 100A is detectedfrom the position of the loop coil from which the AC signal istransmitted and the position of the loop coil which receives thefeedback signal from the position indicator 100A.

In this case, since the feedback signal from the position indicator 100Avaries in response to variation of the resonance frequency of theresonance circuit depending upon the value of the capacitance of thevariable capacitor configured from the writing pressure detectioncircuit 109, the position detection system 200A detects the writingpressure information from the variation of the frequency (or variationof the phase).

Further, since the capacitor 113 is placed into a connection state or adisconnection state with respect to the resonance circuit in response toswitching on or off of the side switch 143, the resonance frequency ofthe resonance circuit varies in response to switching on and off of theside switch 143. The position detection system 200A detects side switchinformation according to switching on and off of the side switch 143from a variation of the frequency (or a variation of the phase) of thefeedback signal from the position indicator 100A.

It is to be noted that, in the position indicator 100A of theconfiguration type 6, identification information is transmitted to thewireless communication circuit of the position detection system 200Athrough the transmission circuit of the wireless communication circuit142.

If the pen type information received from the position detection systemthrough the reception circuit of the wireless communication circuit 142of the position indicator 100 is the configuration type 7, then such aposition indicator 100B as depicted in FIG. 19B is configured by thesignal transmission control circuit 141. In particular, in the presentconfiguration type 7, the parallel resonance circuit is configured fromthe coil 111 and the capacitor 112. Further, the writing pressureinformation, side switch information and identification information areall transmitted to the wireless communication circuit of a positiondetection system 200B through the transmission circuit of the wirelesscommunication circuit 142.

The sensor of the position detection system 200B which is used togetherwith the position indicator 100B of the configuration type 7 and sendsthe configuration type 7 as pen type information to the positionindicator 100B has a same configuration as that of the sensor of theposition detection system 200A and transmits a transmission signal (ACsignal) of the frequency fa from a loop coil to the position indicator100B.

In the position indicator 1006, an AC signal from the position detectionsystem 200B is received by the resonance circuit through electromagneticcoupling and then the AC signal is fed back from the resonance circuitto the position detection system 200B similarly to the positionindicator 100A. In the position detection system 200B, a positionindicated by the position indicator 100B is detected similarly as in theposition detection system 200A.

The position detection system 200B of this configuration type 7 does nothave a function for monitoring a variation of a frequency or a phase ofa feedback signal to detect additional information. Further, theposition detection system 200B decodes additional information receivedthrough the wireless communication circuit to acquire writing pressureinformation, side switch information and identification information.

If the pen type information received from the position detection systemthrough the reception circuit of the wireless communication circuit 142of the position indicator 100 is the configuration type 8, then such aposition indicator 100C as depicted in FIG. 19C is configured by thesignal transmission control circuit 141. In particular, in the positionindicator 100C of the configuration type 8, the parallel resonancecircuit configured from the coil 111 and the capacitor 112 is coupled tothe oscillator 145 to configure an oscillation circuit 145S. Thus, anoscillation signal from the oscillation circuit 145S is transmitted to aposition detection system 200C through the parallel resonance circuitconfigured from the coil 111 and the capacitor 112.

Further, the writing pressure information, side switch information andidentification information are all transmitted to the wirelesscommunication circuit of the position detection system 200C through thetransmission circuit of the wireless communication circuit 142.

Further, the sensor of the position detection system 200C which is usedtogether with the position indicator 100C of the configuration type 8and sends the configuration type 8 as the pen type information to theposition indicator 100C is configured such that, though not depicted,pluralities of loop coils are arrayed in an X direction and a Ydirection orthogonal to each other.

Further, the position detection system 200C receives an AC signaltransmitted from the position indicator 100C by a loop coil throughelectromagnetic coupling. Then, the position detection system 200Cdetects the position indicated by the position indicator 100C from thepositions in the X direction and the Y direction of the loop coil bywhich the AC signal is received.

It is to be noted that also the configuration types 6 to 8 describedabove are examples, and various other configuration types are availablefor a position indicator and a position detection system of theelectromagnetic coupling scheme, and it is a matter of course that theposition indicator of the present disclosure can be configured so as tobe compatible with the various configuration types. For example, while,in the examples of the configurations types 6 to 8 described above,identification information is not transmitted through the resonancecircuit, a different configuration type may be used such thatidentification information is transmitted as an ASK modulation signal oran OOK signal from the core member 107 side by controlling switching onand off of a resonance action of the resonance circuit or an oscillationaction of the oscillation circuit 145S.

Other Embodiments or Modifications

Although the writing pressure detection circuits 9 and 109 of theembodiments described above are configured such that they use a variablecapacitor whose capacitance is variable in response to a writingpressure by sandwiching a dielectric member between a first electrodeand a second electrode and making one of the first electrode and thesecond electrode movable in an axial direction in response to thewriting pressure, the writing pressure detection circuit is not limitedto this configuration. Also, it is possible to configure the writingpressure detection circuit 9 using such a semiconductor element whosecapacitance is variable in response to a writing pressure as disclosed,for example, in Japanese Patent Laid-Open No. 2013-161307.Alternatively, the writing pressure detection circuit may be configuredby using a structure or an element having not a capacitance but aninductance value or a resistance value which is variable in response tothe writing pressure.

Further, the additional information is not limited to any of writingpressure information, side switch information and identificationinformation as described hereinabove, but other various types ofinformation such as remaining amount information of a battery may beused as the additional information.

Further, while, in the foregoing description of the embodiments, thedriving power supply for the position indicator is a battery, acapacitor for accumulating a power supply voltage may be provided in theposition indicator such that the capacitor may be used as a drivingpower supply. In this case, the configuration for accumulating a powersupply voltage in the capacitor may be a configuration of a chargingcircuit which receives electric energy from the outside throughelectromagnetic induction or electric field coupling to perform chargingor may be a configuration wherein a charging terminal is furtherprovided on the position indicator such that charging current issupplied from a charging apparatus for exclusive use through thecharging terminal. Then, the electric energy (electromagnetic energy orelectric field energy) from the outside may be supplied from theposition detection apparatus to the position indicator or may besupplied from a power supplying apparatus for exclusive use.

Further, while, in the embodiments described hereinabove, the positionindicator includes two transmitters including a center electrode and awireless communication circuit, it may include three or moretransmitters.

It is to be noted that, in the description of the position indicator ofeach of the embodiments described hereinabove, by moving the positionindicator close to the sensor of the position detection system, theposition indicator is automatically placed into that of a configurationtype compatible with the position detection system. However, not by theposition detection system but the position indicator may be configuredsuch that, by communicating with an external apparatus such as apersonal computer which is communicatable with the wirelesscommunication circuit of the position indicator and selecting aconfiguration type through the external apparatus such as a personalcomputer, the position indicator can be set to that of the selecteddesired configuration type.

Alternatively, the position indicator may be configured such that itincludes a switch for switchable setting of a configuration type suchthat the position indicator can be set to that of a desiredconfiguration type by a switching operation by the switch for theswitchable setting. In particular, for example, the example of FIG. 18is configured such that a pushbutton switch 146 which can be manuallyoperated by the user is provided on the housing 103 such that adepression operation signal of the pushbutton switch 146 is supplied tothe signal transmission control circuit 141. In this case, every timethe pushbutton switch 146 is depressed, for example, by the user, thesignal transmission control circuit 141 performs control so as to changethe configuration type. It is to be noted that, also in the example ofFIG. 1, a pushbutton switch may naturally be provided similarly.

DESCRIPTION OF REFERENCE SYMBOLS

-   -   1, 1A to 1E, 100A to 100C . . . Position indicator,    -   2, 2A to 2D, 200A to 200C . . . Position detection system,    -   3 . . . Housing,    -   31 . . . Insulator portion,    -   32 . . . Conductor portion,    -   5 . . . Battery,    -   6 . . . Peripheral electrode,    -   7 . . . Center electrode,    -   8 . . . Shield member,    -   9 . . . Writing pressure detection circuit,    -   40 . . . Printed wiring board,    -   41 . . . Signal transmission control circuit,    -   42 . . . Wireless communication circuit,    -   43 . . . Side switch,    -   44 . . . ID memory,    -   45, 46 . . . Oscillator,    -   48 . . . Power supply switch,    -   410 . . . Control circuit,    -   411 . . . Pen type decision circuit

1. A position indicator, comprising: a first transmitter; a second transmitter; an inputting circuit which, in operation, accepts an input from outside of the position indicator; a signal generation circuit which, in operation, generates a position detecting signal; a plurality of additional information generation circuits which, in operation, generate a plurality of types of additional information; and a controller which, in operation, controls, based on the input accepted by the input circuit, transmission of the position detecting signal through the first transmitter and controls, based on the input accepted by the input circuit, transmission of additional information generated by the plurality of additional information generation circuits from the first transmitter or the second transmitter.
 2. The position indicator according to claim 1, wherein: the controller, in operation, controls one or more switching circuits to configure the position indicator in a plurality of configuration types and the input accepted by the input circuit relates to a selection from among the plurality of configuration types; and the controller, in operation, controls transmission of the position detecting signal through the first transmitter in response to a configuration type selected from among the plurality of configuration types based on the input accepted by the input circuit, and controls transmission of the additional information generated by the plurality of additional information generation circuits from the first transmitter or the second transmitter in accordance with the selected configuration type.
 3. The position indicator according to claim 1, wherein: the input circuit, in operation, accepts information from an external apparatus; and the controller, in operation, controls transmission of the position detecting signal through the first transmitter based on information accepted by the input circuit, and controls transmission of the additional information generated by the plurality of additional information generation circuits from the first transmitter or the second transmitter.
 4. The position indicator according to claim 3, wherein: the external apparatus is a position detection system; and transmission of a signal from the first transmitter to the position detection system is performed through capacitive coupling between the first transmitter and the position detection system, and transmission of a signal from the second transmitter to the position detection system is performed by wireless communication, the second transmitter being configured to perform wireless communication according to a defined communication protocol independently of the first transmitter.
 5. The position indicator according to claim 3, wherein: the external apparatus is a position detection system; and transmission of a signal from the first transmitter to the position detection system is performed through electromagnetic coupling between the first transmitter and the position detection system, and transmission of a signal from the second transmitter to the position detection system is performed by wireless communication, the second transmitter being configured to perform wireless communication according to a defined communication protocol independently of the first transmitter.
 6. The position indicator according to claim 3, wherein: the first transmitter includes a center electrode disposed at one end in an axial direction of an elongated cylindrical housing and disposed on a central axis of the cylindrical housing, and a plurality of peripheral electrodes surrounds the center electrode.
 7. The position indicator according to claim 1, wherein: the input circuit is a receiver which, in operation, receives a signal from an external apparatus; and the controller, in operation, controls transmission of the position detecting signal through the first transmitter based on a reception signal received by the receiver, and controls transmission of the additional information generated by the plurality of additional information generation circuits from the first transmitter or the second transmitter.
 8. The position indicator according to claim 7, wherein: the signal generation circuit includes a plurality of signal generation circuits; and the controller, in operation, determines which one of the plurality of signal generation circuits generates the position detecting signal based on the reception signal by the receiver.
 9. The position indicator according to claim 7, wherein: the external apparatus is a position detection system; and reception of a signal from the position detection system by the receiver is performed by wireless communication, the receiver being configured to perform wireless communication according to a defined communication protocol.
 10. The position indicator according to claim 7, wherein: the external apparatus is a position detection system; and the receiver includes a first reception circuit which, in operation, receives a signal from the position detection system by wireless communication, the receiver being configured to perform wireless communication according to a defined communication protocol, and a second reception circuit which, in operation, receives a signal from the position detection system through capacitive coupling between the second reception circuit and the position detection system.
 11. The position indicator according to claim 7, wherein: the external apparatus is a position detection system; and the first transmitter, in operation, receives a signal from the position detection system through a reception electrode and transmits the signal to the position detection system through a transmission electrode.
 12. The position indicator according to claim 11, wherein: the reception electrode and the transmission electrode of the first transmitter are formed from a center electrode disposed at one end in an axial direction of an elongated cylindrical housing and disposed on a central axis of the cylindrical housing, and a peripheral electrode surrounds the center electrode.
 13. The position indicator according to claim 7, wherein: the external apparatus is a position detection system; and when a signal from the position detection system is not received by the receiver, the controller, in operation, determines that a configuration type in which the position detecting signal is not transmitted from the first transmitter is available.
 14. The position indicator according to claim 7, wherein: the external apparatus is a position detection system; a signal from the position detection system received by the receiver indicates a configuration type of the position indicator; and the position indicator further comprises a memory which stores information regarding the configuration type and relating to control, by the controller, of signals to be transmitted from the first transmitter and the second transmitter.
 15. The position indicator according to claim 7, wherein: the first transmitter includes a conductor disposed at one end in an axial direction of an elongated cylindrical housing; and when the controller determines that the position detecting signal is to be transmitted based on the reception signal received by the receiver, the controller performs control to transmit the position detecting signal through the conductor of the first transmitter.
 16. The position indicator according to claim 15, wherein: the conductor disposed at the one end is an electrode core projecting from an opening provided at the one end in the axial direction of the housing or an electrode disposed at a peripheral portion of the electrode core.
 17. The position indicator according to claim 15, further comprising: a pressure detection circuit which, in operation, detects a pressure applied to one end of the conductor in the axial direction of the housing, wherein the additional information includes information regarding the pressure detected by the pressure detection circuit.
 18. The position indicator according to claim 1, further comprising: a memory that stores identification information, wherein the additional information includes the identification information stored by the memory.
 19. The position indicator according to claim 1, further comprising a switch which, in operation, accepts a manual operation of a user, wherein the additional information includes information regarding a state of the switch.
 20. The position indicator according to claim 19, wherein: the second transmitter, in operation, transmits a transmission signal including identification information of the second transmitter; and the identification information as the additional information transmitted from the first transmitter and the identification information of the second transmitter are same as each other.
 21. The position indicator according to claim 1, wherein: the input circuit is a switch provided on a housing; and the controller, in operation, controls transmission of the position detecting signal through the first transmitter based on switch information acquired from the switch, and controls transmission of the additional information generated by the plurality of additional information generation circuits from the first transmitter or the second transmitter. 